Quick fix: Simmer the curry uncovered to reduce it, or stir in a slurry of 1 tsp cornflour mixed with cold water. Lentils, ground almonds or a spoon of tomato purée also thicken it fast.
Why it happens
- Too much stock, water or tinned tomato liquid added at the start.
- Cooking with the lid on the whole time, so steam can't escape.
- Watery vegetables (like courgette or mushrooms) releasing liquid as they cook.
- Not browning the onions and paste enough, so you rely on extra liquid for flavour.
How to fix it now
- Turn up the heat and simmer uncovered for 10–15 minutes to reduce the sauce.
- Or stir in a cornflour slurry (1 tsp cornflour + 1 tbsp cold water) and cook for a couple of minutes.
- Add 2–3 tbsp red lentils or 1–2 tbsp ground almonds to absorb liquid and add body.
- Stir in a spoonful of tomato purée and cook it out.
How to prevent it next time
- Add liquid gradually — you can always loosen later, but reducing takes time.
- Brown the base of onions, garlic and spices well before adding liquid.
- Simmer with the lid off for the last stretch.